STEM CELL TECHNOLOGY

ROLE OF STEM CELLS

In the scalp, epithelial stem cells differentiate into hair follicles, sebaceous glands, or interfollicular epidermis. Each lineage maintains its own reservoir of stem cells for normal tissue homeostasis and renewal. In response to disease or injury, some stem cells mobilize to repair tissues whose resident stem cells have been damaged or removed, responding to signals to migrate and proliferate in new locations.

Follicles display a robust regenerative capacity that normally maintains hair growth throughout our lifetimes. Understanding how stem cells repair wounds is important to understanding how they regrow hair.

At the site of each hair is a bulge of cells that divide less frequently than other epithelial cells. They are activated at the start of each growth cycle to generate a new follicle. In one laboratory experiment, stem cells from a single bulge were removed from a hairy mouse and grafted onto a hairless mouse, and they generated new follicles that cycled normally. In another study, when confronted with stem cells from the wing of a chick, epidermis from its leg actually produced feathers.

Stained slide of normal epidermis and dermis, with a benign intradermal nevus

HAIR-GROWTH CYCLE

The scalp and its appendages — hair follicles and sebaceous glands — provide protective barriers that keep microbes out and bodily fluids in. They resist environmental assaults and wounds through continuous self renewal.

Stem cells serve to create this new epidermal tissue. They proliferate within the stratum basale, also called the stratum germinativum, which is the basal layer of epithelial cells that divide continually to replace the keratin-rich cells of the stratum corneum as they migrate toward the surface and slough away.

Epidermis is remarkable in its ability to generate appendages. On the scalp, the primary appendages are the pilosebaceous units, containing follicles to manufacture hair and sebaceous glands to lubricate the cutaneous surface. Morphogenesis begins with a downward incursion of the epidermis into the underlying dermis to form a placode — a platelike thickening of embryonic ectoderm — in a process dependant on cues from neighboring cells.

Underlying dermal cells condense to form a papilla, which is the vascular process that nourishes the root. As the follicle develops, it becomes encapsulated in a rich matrix of cells. Then stem cells in a bulb, located roughly midway down the follicular process, proliferate to form an inner root sheath, which acts as a channel to guide the growing hair shaft.

A period of hair growth, called anagen phase, normally lasts a few years. The following phase, called catagen, lasts a few weeks and involves the apoptosis and disappearance of the lower two thirds of the follicle. Then the dermal papilla migrates up toward the bulge, and the remains of the follicle enter a resting phase, called telogen, and wait for chemical signals to begin the cycle all over again.

Except for follicles affected by androgenic alopecia (male pattern baldness) or other disease, a single follicular process cycles many times throughout a person’s life. The cyclic nature of degeneration and regeneration from the bulge led to the discovery that stem cells were concentrated there.

Even without alopecia, anagen phase shortens, and telogen phase lengthens, accounting for the thinning hair usually found on aging scalps. Perhaps the chemical signaling required to stimulate anagen becomes increasingly difficult to achieve.

STEM CELLS IN REVITA.COR

Our new understanding of follicular stem cells means exciting new developments in biotechnical formulas for hair regrowth, such as Revita.COR conditioner. We know that embryonic stem cells can develop into any tissue, that normal skin contains reserves of such cells to regenerate itself after wounding, and that stem cells from one animal can develop into follicles in another animal.

New applications for bulge stem cells would be to treat hair follicle disorders. Cultured basal epidermal keratinocytes already treat burn patients. However, human stem cells are difficult to obtain, and their use is fraught with ethical dilemmas.

Revita.COR overcomes these hurdles by employing plant-based stem cells, which exhibit many of the same properties and much of the same plasticity as human cells. A revolutionary botanical agent derived from plant stem cells is now showing evidence of protecting and stimulating human epidermal stem cells and preventing many of the signs of scalp aging.

Extending the vigor of human epidermal stem cells is now the cutting edge of biotechnical research into hair regrowth. Current in-vitro experimentation demonstrates that active phyto-compounds can stimulate the growth of human mesenchymal stem cells and help to protect them from ultraviolet radiation attack.

In experiments conducted on hair follicles, plant-based stem-cell extracts rejuvenate follicular cells and delay their senescence.

HAIR GROWTH BENEFITS

So Revita.COR conditioner offers unprecedented new potential to prolong the health of the human scalp and the productivity of its hair follicles, thus delaying baldness and minimizing its adverse effects, by applying plant-based stem cells.